From: Sinan Kaya <okaya@codeaurora.org>
To: linux-mips@linux-mips.org, arnd@arndb.de, timur@codeaurora.org,
sulrich@codeaurora.org
Cc: linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Sinan Kaya <okaya@codeaurora.org>,
Ralf Baechle <ralf@linux-mips.org>,
James Hogan <jhogan@kernel.org>,
Paul Burton <paul.burton@mips.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v3 1/2] MIPS: io: prevent compiler reordering on the default writeX() implementation
Date: Tue, 3 Apr 2018 08:55:03 -0400 [thread overview]
Message-ID: <1522760109-16497-1-git-send-email-okaya@codeaurora.org> (raw)
writeX() has a strong ordering semantics with respect to memory updates.
In the abscence of a write barrier or a compiler barrier, commpiler can
reorder register and memory update instructions. This breaks the writeX()
API.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
arch/mips/include/asm/io.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 0cbf3af..fd00ddaf 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -307,7 +307,7 @@ static inline void iounmap(const volatile void __iomem *addr)
#if defined(CONFIG_CPU_CAVIUM_OCTEON) || defined(CONFIG_LOONGSON3_ENHANCEMENT)
#define war_io_reorder_wmb() wmb()
#else
-#define war_io_reorder_wmb() do { } while (0)
+#define war_io_reorder_wmb() barrier()
#endif
#define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq) \
--
2.7.4
next reply other threads:[~2018-04-03 12:55 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-03 12:55 Sinan Kaya [this message]
2018-04-03 12:55 ` [PATCH v3 2/2] MIPS: io: add a barrier after register read in readX() Sinan Kaya
2018-04-06 1:34 ` Sinan Kaya
2018-04-06 18:15 ` Sinan Kaya
2018-04-06 21:26 ` James Hogan
2018-04-07 21:43 ` Sinan Kaya
2018-04-11 17:10 ` Sinan Kaya
2018-04-11 20:26 ` James Hogan
2018-04-11 20:48 ` Sinan Kaya
2018-04-11 17:04 ` Maciej W. Rozycki
2018-04-12 21:51 ` James Hogan
2018-04-12 21:58 ` James Hogan
2018-04-12 22:38 ` Sinan Kaya
2018-04-12 22:20 ` Sinan Kaya
2018-04-13 15:41 ` David Laight
2018-04-13 16:36 ` Sinan Kaya
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